1. Field of the Invention
The present invention relates to a novel coated powder exhibiting super-dispersibility and, more particularly, it relates to surface-treated powder comprising a powder usable for cosmetics, and coating layers of surface treating agents containing a layer A that is a solid at room temperature and a layer B that is a liquid at room temperature, each formed on at least a portion of the powder particle surface, and to a cosmetic containing the surface-treated powder. More particularly, it relates to a surface-treated powder having coating layers of surface treating-agents, in which the coating layer of a surface treating agent of layer A as a first layer, and the coating layer of a surface treating agent of layer B as a second layer, are each formed on at least a portion of the powder particle surface. Layer A is a coating layer of a surface treating agent that is a solid at room temperature and contains at least one compound selected from the compounds contained in reactive organo polysiloxane, polyolefin, hydrogenated lecithin, including its salt forms, N-acylamino acid, including its salt forms, fatty acid, including its salt forms, and dextrin fatty acid esters. Layer B is a coating layer of a surface treating agent that is a liquid at room temperature, and contains at least one compound selected from the compounds contained in organo polysiloxane modified at its sole terminal end with a functional group, alkylsilane modified at its sole terminal end with a functional group, and branched fatty acid, and to a cosmetic containing the surface-treated powder.
The surface-treated powder of the present invention exhibits super-dispersibility, so that, when the surface-treated powder of the present invention is mixed into a formula (composition for cosmetics) not containing an oleophilic liquid, that is a system containing only powders, it exhibits superior dispersibility. Moreover, if the surface-treated powder of the present invention is mixed into a system containing oleophilic liquid; the surface-treated powder is superior in affinity to the liquid and hence superior in dispersibility and dispersion stability. Moreover, the surface-treated powder of the present invention drastically improves the functions of the powder base that vary according to the dispersed state, for example, adhesion to the skin, aesthetic feeling (using touch), covering power, coloring power, shielding power against UV or IR rays and optical characteristics (properties), as compared to those of conventional surface-treated powders.
Therefore, the cosmetic containing the surface-treated powder according to the present invention can be appreciably improved as to the functions as cosmetics.
The powder obtained in this manner can be applied not only to cosmetics, but also to surface-treated powders that finds application in a variety of other technical fields such as additives for plastics, inks, paints, toners (magnetic powders) and the like.
2. Description of the Related Art
Powders mixed into cosmetics are oleophilized in order to eliminate the powdery feeling, reduce physical stimuli to the skin, improve adhesiveness to the skin, improve dispersibility in an oleophilic liquid and improve wear on the skin. These oleophilized powders are usually mixed with an oily component and used in formulations. As the powder materials approaches its primary particles when mixed or dispersed, the powder material exhibits its optimum potential of its functional properties. In order to reach this optimum point of functionality, which relates to adhesion, aesthetic feeling (using touch), covering power, coloring power, optical properties, absorption and/or scattering of UV and IR rays to the fullest extent, excellent affinity as well as excellent dispersibility of the powder to an oily agent is necessary, because poor affinity with the oily agent leads to flocculation to render it impossible to display its maximum potential characteristics.
In order to solve this problem, it has been proposed to have the surface of the powder material coated with an oleophilic material. Although the adhesion to the skin of the powder material, as well as its rough feeling is improved by this method to some extent, the powder material becomes flocculated by the surface treating agent itself such that dispersibility does not reach its optimum state. Furthermore, in order to disperse the powder material into an oleophilic liquid, it is necessary to assort a large quantity of surfactants to improve its affinity into the oil and to achieve dispersion stability.
On the other hand, powdered organic materials, exemplified by polyethylene powder, nylon powder, polystyrene powder and methyl methacrylate powder, etc. is itself oleophilic such that it is in many cases better in dispersibility into an oleophilic liquid than the inorganic material. However, organic material suffers from drawbacks such as extremely poor adhesion to the skin and a tendency to be statically charged and therefore become flocculated, which lowers its dispersibility, etc., significantly. In order to improve upon this, a variety of surface treating methods have so far been proposed.
This kind of surface treating method routinely coats the material with organic surface treating agents, such as silicones, organic silanes, N-acylamino acids, fatty acids, hydrogenated lecithin, fluorine compounds, polyethylene, ester-based oily agents and the like. Specifically, there have been proposed a surface treating method with methyl hydrogen polysiloxane (Refer to Japanese Patent Kokai Publications JP-A-60-163973, JP-A-61-127767, JP-A-61-190567, JP-A-61-215216, JP-A-63-30407, JP-A-63-139015, JP-A-63-165461, JP-A-1-110540, JP-A-3-163172 and JP-A-4-246474, and Japanese Patent Kokoku Publications JP-B-1-54379, JP-B-1-54380 and JP-B-1-54381.), a surface treating method with various silane coupling agents (Refer to Japanese Patent Kokai Publications JP-A-62-177070, JP-A-2-218603 and JP-A-4-193816.), a method for surface-treating with other silicones (Refer to Japanese Patent Kokai Publications JP-A-4-202109, JP-A-4-202110, JP-A-4-202111, JP-A-5-86368, JP-A-7-206637, JP-A-7-206638, JP-A-7-207187 and JP-A-11-80588.), and a method for surface-treating with alkylsilane (Refer to Japanese Patent Kokai Publications JP-A-61-204112, JP-A-64-90111, JP-A-8-92052, JP-A-8-104606 and JP-A-8-104612.).
Further, a method for surface-treating with N-acylamino acids has been proposed in, for example Japanese Patent Kokai Publications JP-A-61-737775, JP-A-61-69709, JP-A-3-200879, JP-A-5-186706, JP-A-9-328413, JP-A-10-226626 and the like, whilst a method for coating with fatty acids is proposed in Japanese Patent Kokai Publications JP-A-60-69011 and the like, and a method for surface-treating with hydrogenated lecithin is proposed in Japanese Patent Kokai Publications JP-A-60-184571, JP-A-60-190705 and the like.
There are also known methods of enhancing the function of the powdered base material by coating the powder material with plural surface treating agents in combination. Specifically, powder material coated with methyl hydrogen polysiloxane and trimethyl siloxy silicic acid (Refer to Japanese Patent Kokai Publications JP-A-7-62263 and the like.), powder material coated with a titanium coupling agent or an alkylsilane compound, and an oleophilic material not having a functional group (Refer to Japanese Patent Kokai Publications JP-A-11-29719 and the like.) and powder material coated with methyl hydrogen polysiloxane, trimethyl siloxysilicic acid and cross-linked methyl polysiloxane in combination (Refer to Japanese Patent Kokai Publications JP-A-11-80588 and the like.).
1. Problem to be Solved by the Invention
However, there are as yet left problems to be solved in the aforementioned conventional surface treating methods.
First, the aforementioned surface treating agents are mostly solid at ambient room temperature on the surface of the powder particle material, so that, when the surface treating agent is applied to the powder particle material, smooth feeling and adhesion to the skin is improved to some extent, however, the particles tend to flocculate during the coating process. This results in poor dispersion when mixing the powder material, in particular to low affinity oleophilic liquids, and insufficient dispersibility and dispersion stability. For example, titanium dioxide or iron oxide contained in make-up cosmetics, etc., termed as xe2x80x9cpigment gradexe2x80x9d, with a particle size of 0.1 to 0.3 xcexcm, is poor in dispersibility in an oily agent, and therefore does not exhibit optimum covering power or coloring power. In many cases, evaluation only of the covering power or coloring power demonstrates that the powder material not surface-treated is better than the surface-treated material.
When the steps of pulverization and dispersion are repeated, problems arises from the point of process complexity and high cost. If a surfactant is assorted as a dispersion stabilizer, there are undesirably imposed constraints on the development of formulation variety and amount that can be used. In addition, the surface treating agent is poor in affinity to an oleophilic liquid and insufficient in dispersibility such that a difference undesirably tends to be produced, between the application color and appearance color.
If, in an attempt to improve smoothness and adhesion to the skin of an extender, such as mica or sericite, the amount of the surface treating agent is increased, flocculation of particles progresses further. Furthermore increasing the amount of solid surface treatment increases the coating thickness, thereby giving the particle a heavy feeling and a loss of smoothness.
In the case of pigmentary grade titanium dioxide or iron oxide assorted into e.g., nail lacquer, color demarcation or separation tends to be produced with time due to poor dispersion stability into the organic solvent. There is a need of a surface-coated powdered material effective to prevent this. At the present moment organic modified clay minerals, which give an increase in thixotropy, are used in order to accommodate for the surface-coated powder material to prevent precipitation and color separation.
In order to improve the properties of adhesion on to the skin, water proofness, achieve high solid content O/W type emulsions or creams with low oily phase content, increase solid content into oleophilic components for pre-dispersion pastes that are used to improve the handling of fine particulate powders, and achieve high stability, of fine titanium dioxide, zinc oxide, cerium oxide, zirconium oxide or silicon oxide, used for shielding UV or IR light, conventional coatings are not sufficient.
On the other hand, the present inventors have reported that, if a powdered material is coated with a straight-chained dimethyl polysiloxane modified at the terminal end with a trialkoxy group, there is obtained a powder material which is free from flocculation of the particles of the powder material, has a smooth feeling, good adhesion to the skin, and superior spreading properties for colored pigments (Refer to Japanese Patent Kokai Publications JP-A-5-339518 and JP-A-7-196946.). With this surface treating agent, a liquid coating layer is formed at room temperature even after coating thereof on the particle surface, so that it has excellent adhesion to the skin, a lubricious feeling (slipperiness), and excellent affinity or dispersibility in an oleophilic liquid compared to conventional surface treated particulates. However, when one tries to further increase these functions, dispersion in the oleophilic liquid is not necessarily improved even when the coating quantity is increased. For this reason a coated powdered material is desired, which can further improve these functions, such as adhesion to the skin, aesthetic feeling (using touch), covering power, coloring power, UV or IR light shielding power and other optical properties, and is superior in affinity and dispersibility in the oleophilic liquid.
In addition, formulations for cosmetic are recently designed to exploit the optical performance of the powder material. Optical characteristics of powder materials are determined depending on the particle shape, particle size distribution, and refractive index of the powder material. These inherent optical properties of the material cannot be displayed readily if the material is poor in dispersibility, thus necessitating excess amounts of the material in the formulation. This reinforces the demand for a powder material having superior dispersibility.
It is an object of the present invention to provide a coated powdered material obtained on surface-treating a powdered material for cosmetic, with which dispersibility of the powdered material and various functions proper to the powdered material, such as adhesion to the skin, aesthetic feeling (using touch), covering and coloring power, UV and IR light shielding power and optical properties, maybe improved further, and which is superior in affinity to oleophilic liquids, in dispersibility and in dispersion stability.
Based on the following concept and experimentation, the present inventors have completed a surface-treated powdered material which, by applying two layers of surface treating agents thereon, displays excellent (super)-dispersibility, in particular superior dispersibility in oleophilic liquids. That is, the present inventors conducted perseverant searches into a stable surface treating agent which displays strong water repellency and oleophilicity over an extended period of time as a first coating layer (layer A) formed on the outermost surface of the particles of the powdered material, and which gives a homogeneous, extremely strong surface coated layer; and into a surface treating agent which as a second coating layer (layer B) is able to protect the first coating layer against mechanical impacts, exhibits high affinity to oleophilic liquids, and which thereby gives superior dispersibility and dispersion stability. Thus, we have found that, by coating the powdered material (substrate) with a solid surface treating agent, as a first layer, and by coating the substrate, having the first layer, with a liquid surface treating agent as a second layer, a surface-treated powdered material can be produced which displays hitherto unprecedented high performance.
That is, the present inventors conducted perseverant searches towards accomplishing the above object, and found that, if at least two layers, preferably a layer A, on the powder particle surface and a layer B on the layer A, on at least a portion of the surface of the powder usable for cosmetics, specifically on the entire powder surface or on a portion thereof, to form a layer coated with a surface treating agent that is a liquid at room temperature, with layer A being a coating layer of a surface treating agent that is a solid at room temperature, containing at least one compound selected from the compounds contained in a reactive organo polysiloxane, a polyolefin, a hydrogenated lecithin, including its salt form such as a metal salt, a N-acylamino acid, including its salt form such as a metal salt, a fatty acid, including its salt form such as a metal salt, and a dextrin fatty acid ester, and with layer B being a coating layer of a surface treating agent that is a liquid at room temperature, containing at least one compound selected from the compounds contained in an organo polysiloxane modified at its sole terminal end with a functional group, an alkylsilane modified at its sole terminal end with a functional group and a branched fatty acid, the resulting novel coated powder is extremely effective as a powder achieving the above objective, with the powder being particularly excellent in affinity to and hence in dispersibility in an oleophilic liquid. This finding has led to the completion of the present invention.
Thus, the present invention resides in a surface-treated powder comprising a powder usable for cosmetics, and coating layers of surface treating agents of a layer A and a layer B, each formed on at least a portion of the powder particle surface,
wherein the layer A is a coating layer of a surface treating agent that is a solid at room temperature, the coating layer containing at least one compound selected from the compounds contained in the group consisting of a reactive organo polysiloxane, a polyolefin, a hydrogenated lecithin, including its salt forms, an N-acylamino acid, including its salt forms, a fatty acid, including its salt forms, and a dextrin fatty acid ester; and
wherein the layer B is a coating layer of a surface treating agent that is a liquid at room temperature, the coating layer containing at least one compound selected from the compounds contained in the group consisting of an organo polysiloxane modified at its sole terminal end with a functional group, an alkylsilane modified at its sole terminal end with a functional group, and a branched fatty acid.
The present invention also is directed to a cosmetic containing the surface-treated powder.
On the powder thus treated, the layer A and the layer B are solid and liquid at room temperature, respectively.
As a particularly preferred embodiment of the present invention, the surface-treated powdered material (powder) sequentially coated with a layer A and with a layer B in this order is mainly explained as embodying the present invention. The present invention is, however, intended to cover the following modifications as explained, including the preferred embodiment without being limited thereto.
The powdered material (substrate) is such a powdered material which can be used for cosmetics, and which has an average particle size preferably of about 500 to 0.01 xcexcm and more preferably of about 100 to 0.01 xcexcm.
There is no particular limitation to the powdered material (substrate) to be surface-treated for use in the present invention, provided the powdered material (substrate) is one routinely used for cosmetics. In addition however, the powdered material (substrate) can be used not only for cosmetic but also for surface-treated powders used in a wide range of fields of application such as additives for plastics, inks, paints or toners (magnetic powders). The average particle size is preferably tens of microns (xcexcm) to about 0.01 micron (xcexcm).
As for the methods for measuring the particle size, the laser diffraction method or a precipitation method is used for particles with a particle size of 0.1 xcexcm or greater, whereas a photon correlation method or an electron microscope is used for particles with a particle size of 0.1 xcexcm or less.
For example, inorganic powdered materials may be enumerated by mica, sericite, talc, kaolin, synthesized mica, calcium carbonate, magnesium carbonate, magnesium silicate, aluminum silicate, calcium phosphate, silicic anhydride, alumina, magnesium oxide, aluminum hydroxide, barium sulfate, magnesium aluminosilicate, magnesium aluminometasilicate, boron nitride, zeolite, hydroxy apatite, ceramic powders and the like, as an extender.
White-colored pigments may be enumerated by titanium dioxide, zinc oxide and cerium oxide, while colored pigments may be enumerated by red iron oxide, yellow iron oxide, black iron oxide, chromium oxide, chromium hydroxide, Prussian blue, ultramarine blue, carbon black, low order titanium oxide, mango violet and the like. Pearl pigments may be enumerated by bismuth oxychloride, mica titanium, fish scale foil and the like, while fine particulate powders may be enumerated by fine particulate titanium dioxide, fine particulate zinc oxide, fine particulate iron oxide, fine particulate cerium oxide and the like. Finally, some other powdered materials may be enumerated by aluminum powders, stainless steel powders and the like. These powders may be used singly or as a mixture.
These powdered materials may be compounded to form composite pigments if needed. For example, powdered materials comprising inorganic colored pigments, such as red iron oxide, coated with a silicic anhydride, powdered materials comprising of an extender, coated with a fine particulate white-colored pigments, or the like may be used.
Organic powdered materials may be enumerated by polyamide, polyester, polyethylene, polypropylene, polystyrene, polyurethane, vinyl resin, urea resin, phenolic resin, fluorine resin, silicon resin, acrylic acid resin, melamine resin, epoxy resin, polycarbonate resin, divinylbenzene-styrene copolymer, copolymers composed of two or more of the above monomers, celluloid, acetyl cellulose, cellulose, polysaccharides, protein, organic tar dyes and the like.
According to the present invention, the surface of the surface-treated powdered material (powder particle) is covered at least partially with layer A and layer B. Typically, layer A is applied to the surface of the particulate powder in contact therewith, and layer B is applied to layer A in contact therewith. A double coating layer comprising of layer A and layer B are desirably applied to the entire surface of the particulate powder, since thereby the meritorious effect of the present invention can be displayed sufficiently. However, only one of the layers A and B may be present on a certain portion of the powder particle surface, whereas neither layer A nor layer B may be present on an extremely small portion of the surface of the particulate powders, although on extremely rare occasions.
Another distinct layer may also be provided between layers A and B or between layer A and the particle surface of the powdered material (substrate) to the extent without impairing the object of the present invention.
The following explanation is made mainly with respect to powdered materials in which layer A is applied in contact with the surface of the powdered material and layer B is applied in contact with layer A. However, the present invention is not limited to this particular embodiment, as described above.
Layer A is a coating layer of the surface treating agent applied in contact with the surface of the particulate powder and which is a solid at room temperature. On the other hand, layer B is a coating layer of the surface treating agent applied in contact with layer A applied in contact with the surface of the particulate powder. Layer B is a liquid at room temperature. What the inventors mean by the coating layer of the surface treating agent being a solid at room temperature, is that the surface treating agent when coated on the surface of the particulate powder is and remains as a solid at room temperature. Suffice to say, that the coating layer of the surface treating agent is a liquid at room temperature, means that the coating layer of the surface treating agent as coated thereon is and remains as a liquid at room temperature. Therefore, it suffices if layer A and layer B is solid and liquid, respectively, at room temperature as applied to the surface of the particulate powder. It is noted that, prior to coating on the surface of the particles, the surface treating agents in question may be liquid or solid, however, the surface treating agents are needed in the aforementioned state when the surface treating agent is once applied.
Moreover, the surface treating agent is solid or liquid at room temperature means directly that the surface treating agent is solid or liquid at room temperature, furthermore, the liquid state particularly can be identified as possessing a xe2x80x9clubricious feelxe2x80x9d.
It is noted that certain surface treating agents exhibit a lubricious feel even if the agent is solid at room temperature. For example, N-lauroyl-L-lysine, boron nitride, silicone resin powders, silicone rubber powders, poly-tetrafluoroethylene powders and the like are of the lamellar or spherical particle shape and present extremely smooth feeling because of the properties of the compounds in question, so that a powdered material coated with these compounds sometimes present a lubricious feel. However, the meritorious effect proper to the present invention cannot be achieved with these compounds (when used for the layer B).
Layer A is a coating layer of a surface treating agent that is a solid at room temperature, and which contains at least one compound selected from the compounds contained in the group consisting of a reactive organo polysiloxane, polyolefin, such as polyethylene, polypropylene, etc., hydrogenated lecithin, including salts thereof, N-acylamino acid, including salts thereof, and dextrin fatty acid ester. Layer B is a coating layer of a surface treating agent that is a liquid at room temperature, which contains at least one compound selected from the compounds in the group consisting of an organo polysiloxane modified at a sole terminal end with a functional group, an alkylsilane modified at a sole terminal end with a functional group, and a branched fatty acid.
The coating layers A and B formed on the particle surface of the powder material according to the present invention may be construed to be the coating layers of the surface treating agents of the layers A and B in the meaning of the present invention, provided that the aforementioned ingredients used as the layers A and B of the present invention are affixed onto the powdered material.
(Reactive Organo Polysiloxane)
Among the reactive organo polysiloxanes, there are preferably included, organo hydrogen polysiloxane, polyalkoxy organo polysiloxane, triorgano siloxy silicic acid, organopolysiloxane modified at both terminal ends with trialkoxy groups, and the like.
As the reactive organo polysiloxanes used in accordance with the present invention, straight-chained or cyclic reactive organo polysiloxanes, represented by any of the following general formula (1) to (6), are particularly preferred. In these general formulas (1) to (6), plural R1s, that is R1s present not only in one of the general formulas but present in the general formulas (1) to (6) in their entirety, are independent from one another and respectively denote any one of lower alkyl groups with one to four carbon atoms, plural R2s are similarly totally independent from one another and denote any one of hydrogen atoms, hydroxyl groups, and lower alkyl groups with one to four carbon atoms, n denotes an integer not less than two and m denotes zero or an integer, with n+m denoting an integer from 2 to 10000.
(R13SiO)(R1R2SiO)n(R12SiO)m(SiR13)xe2x80x83xe2x80x83(1)

The compound represented by the general formula (1) with n equal to 0 or 1 is poor in reactivity on the surface of the particulate powders and presents a lubricious smooth feeling without assuming a three-dimensional meshed structure. This compound, however, is not desirable, since it fails to take part in rendering the powdered material hydrophobic or oleophilic.
It is more preferred that the compound of organo hydrogen polysiloxane, represented by the general formula (2), has n that is an integer of 3 to 7.
It is more preferred that the compound of organo hydrogen polysiloxane, represented by the general formula (3), has n that is an integer greater or equal to 2 and n+m is an integer of 3 to 7. The aforementioned cyclic hydrogen polysiloxane is ring-opened on the surface of the particulate powders to assume a three-dimensional meshed structure.
It is more preferred that the compound of polyalkoxy organo polysiloxane, represented by the general formula (4), has m that is an integer of 1 to 100 and the value of n/m is greater than or equal to 0.5.
It is sufficient if the reactive organo polysiloxane represented by the above general formulae (1) to (4) may undergo three-dimensional cross-linking reaction to form a resin, that is to be solidified, irrespective of whether or not the reactive organo polysiloxane is cyclic or straight-chained, as described above. The viscosity as measured at 25xc2x0 C. is preferably on the order of 0.5 to 500 cs, more preferably on the order of 0.5 to 100 cs and further more preferably on the order of 1 to 50 cs. If the viscosity is less than 0.5 cs, the reaction is extremely quick so that particulate powders tend to become flocculated. The coating layer formed on the particle surface also becomes extremely vulnerable against shock and tends to peel off. If the viscosity exceeds 500 cs, the oil extends poorly, such that it is difficult to apply the reactive organo polysiloxane uniformly on the surface of the particulate powders. Such a surface treating agent may be exemplified by xe2x80x9cKF-99xe2x80x9d and xe2x80x9cKF-9901xe2x80x9d manufactured by SHIN-ETSU CHEMICAL CO. LTD., xe2x80x9cSH-1107xe2x80x9d manufactured by DOW CORNING TORAY SILICONE CO. LTD., xe2x80x9cTSF484xe2x80x9d and xe2x80x9cTSF483xe2x80x9d manufactured by TOSHIBA SILICONE CO. LTD., xe2x80x9cFZ3704xe2x80x9d and xe2x80x9cAZ6200xe2x80x9d manufactured by NIPPON UNICAR CO. LTD., and the like.
The compound having the following general formula (5) is triorgano siloxysilicic acid.
(R13SiOxc2xd)n(SiO2)mxe2x80x83xe2x80x83(5)
wherein more preferably m and n are integers, m+n is an integer from 2 to 100 and a ratio n/m is a value equal to or less than 1.0.
If the ratio n/m exceeds 1.0, the coating layer on the surface of the particulate powders undesirably is not a hard solid coating layer but becomes an oily smooth coating layer. This oily coating layer is not desirable, since strong hydrophobicity or oleophilicity can not be achieved.
If trimethylsiloxysilicic acid is used in the present invention, agents yielded on replacing the sodium of water glass with a trimethylsilyl group and dissolving this in a solvent, in which the hardness of the hardened coating layer is controlled by an M/Q ratio corresponding to n/m in the above general formula (5) are extensively marketed and advantageously employed. For example, xe2x80x9cKF-7312Fxe2x80x9d, xe2x80x9cKF-7312Jxe2x80x9d, xe2x80x9cKF-7312Kxe2x80x9d, xe2x80x9cKF-9001xe2x80x9d, xe2x80x9cKF-9002xe2x80x9d, xe2x80x9cX-21-5249xe2x80x9d and xe2x80x9cX-21-5250xe2x80x9d, manufactured by SHIN-ETSU CHEMICAL CO. LTD., xe2x80x9cDC593xe2x80x9d, xe2x80x9cBY-11-015xe2x80x9d, xe2x80x9cBY-11-018xe2x80x9d and xe2x80x9cBY-11-022xe2x80x9d manufactured by DOW CORNING TORAY SILICONE CO. LTD., and xe2x80x9cTSF4600xe2x80x9d manufactured by TOSHIBA SILICONE CO. LTD., etc.
The compound having the following general formula (6) is an organo polysiloxane modified at both terminal ends with functional groups and includes organo polysiloxane modified at both terminal ends with trialkoxy groups:
(R23SiO)(R12SiO)n(SiR23)xe2x80x83xe2x80x83(6)
The above compound where n in the above general formula denotes an integer from 1 to 100 is more desirable.
As the organo polysiloxane modified at both terminal ends with functional groups, is employed in the present invention, those having a straight chain or a branched chain of T-shape and having siloxane repetition units of 1 to 100 are preferably used. If the value of n exceeds 100, reactivity with the surface of the particulate powders is lowered, while the as-reacted coating layer becomes a semi-solid (gelated) to liquid state giving a distorted feeling to render it difficult to achieve desirable effects proper to the present invention. The surface treating agent that can be purchased and employed readily includes, for example, xe2x80x9cX-24-9817xe2x80x9d and xe2x80x9cX-24-9221xe2x80x9d manufactured by SHIN-ETSU CHEMICAL CO. LTD., etc.
(Polyolefin)
As examples of polyolefins, such as polyethylene, polypropylene and the like, there is preferably a polyolefin resin having at least one carboxylic group (see, for example, Japanese Patent Kokai Publication JP-A-63-179972 proposed by the present inventors.). For example, low molecular weight polyethylene having a molecular weight of 500 to 20000 and a melting point not lower than 40xc2x0 C., oxidized polyethylene, obtained on oxidizing polypropylene, polyethylene maleate, oxidized polypropylene and the like, these being marketed products, may be used.
(Hydrogenated Lecithin)
The hydrogenated lecithin, including its salt forms, is a glyceride containing phosphoric acid groups, and which is yielded on hydrogenating natural lecithin extracted from egg yolk, soybean, corn, coleseed (rapeseed) or the like and synthetic lecithin, and has an iodine value of preferably 30 or less and more preferably 15 or less. The hydrogenated lecithin in the salt form is preferably a salt of metals, such as Al, Mg, Ca, Zn, Zr and Ti, of a water insoluble hydrogenated lecithin. The hydrogenated lecithin (including its salt form) having a melting point of 50xc2x0 C. or higher, is particularly desirable (See, for example, Japanese Patent Kokai Publications JP-A-60-184571 and JP-A-60-190705 and Japanese Patent Kokoku Publication JP-B-4-58443, proposed by the present inventors.). Conveniently, marketed xe2x80x9chydrogenated egg yolk oil No.5xe2x80x9d manufactured by ASAHI CHEMICAL INDUSTRY CO. LTD., and similarly marketed hydrogenated soybean phospholipid (xe2x80x9cBASIS LS-60 HRxe2x80x9d) manufactured by NISSHIN OIL MILLS, LTD., may be purchased and used.
(N-acylamino Acid)
N-acylamino acid is an amino acid having an acylated amino and/or imino group. The amino acid making up the N-acylamino acid may be a single amino acid or a mixture of plural or many different amino acids. If L-, D- or DL isomers exist for amino acid(s) making up the N-acylamino acid; any suitable one(s) of these isomers maybe used singly or in combination. The naturally existing L-isomer is more preferred.
The amino acids may be enumerated by glycine, alanine, xcex2-alanine, valine, leucine, isoleucine, phenylalanine, proline, threonine, serine, arginine, histidine, lysin, aspartic acid, glutamic acid, tyrosine, methionine, cystine, cystein and the like.
The fatty acids making up the N-acyl derivative may preferably be exemplified by saturated or unsaturated fatty acids with 1 to 23 carbon atoms and fatty acids with 1 to 23 carbon atoms having a saturated or unsaturated alicyclic structure. For example, N-acylated glycine, n-acylated-N-methyl-xcex2-alanine, N-acylated glutamic acid and the salts thereof may be used (see Japanese Patent Kokai Publication JP-A-61-73775 and Japanese patent Kokoku Publication JP-B-1-50202 proposed by the present inventors).
The constituent fatty acids in the N-acylamino acid are preferably long-chain fatty acids, such as caprylic acid, capric acid, lauric acid, myristic acid, isomyristic acid, palmitic acid, isopalmitic acid, stearic acid, isostearic acid, arachic acid, undecylenic acid, oleic acid, myristoleic acid, elaidic acid, linolic acid, linolenic acid, arachidonic acid, coconut oil fatty acid, beef fallow (fat) fatty acid, resin acid (abietic acid) and the like.
N-acylamino aid may be used in the free from or in the salt form(s). The salt form may be enumerated by salts of metals, such as Na, K, Ba, Zn, Ca, Mg, Fe, Zr, Co, Al, Ti and the like, ammonium salts, and a variety of alkanol amines, such as monoethanolamine, diethanolamine, triethanolamine, 2-amino-2-methyl-propanol, 2-amino-2-methyl-1, 3-propanediol, triisopropanolamine and the like.
Conveniently, commercially available products may be purchased and used. For example, N-acylated with coconut oil fatty acid or N-lauroyl-xcex2-alanine (manufactured by KAWAKEN FINE CHEMICAL Co. LTD.), its Ca or Al salts, myristoyl silk amino acid and its Al salt, manufactured by PHYTOCOS INC., FRANCE, and N-lauroyl-L-lysine and N-stearoyl-L-glutamic acid, manufactured by AJINOMOTO CO., INC., are preferred.
The N-acylating method may be any of known methods, such as those shown in Japanese Patent Kokai Publication JP-A-6-25627 and Japanese Patent Kohyou Publication JP-A-7-502010. For example, N-acylamino acid, obtained on N-acylating amino acids, obtained in turn on total hydrolysis of proteins derived from animals, such as silk, pearl and the like, or derived from plants, such as wheat, soybean and the like, using e.g., long-chain fatty acids, and further in the salt form on forming corresponding salts, where required, may be used as appropriate. As the amino acids used for preparing the N-acyl forms, at least 14 amino acids, namely glycine, L-alanine, L-valine, L-leucine, L-isoleucine, L-phenylalanine, L-proline, L-threonine, L-serine, L-arginine, L-histidine, L-lysine, L-aspartic acid and L-glutamic acid, are preferably contained. N-acyl forms of L-tyrosine, L-methionine, L-cystine, L-cystein and/or the like, may also be contained.
(Fatty Acid)
As fatty acids used in the present invention, those explained in connection with the fatty acids constituting the aforementioned N-acylamino acids, including its salt forms thereof, maybe used. As for the salt forms, those explained in connection with the n-acylamino acid in the salt form hold true unchanged. In particular, straight-chained saturated fatty acids, with 12 to 26 carbon atoms, such as fatty acids, including lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, lignoceric acid and cerotic acid, or the salts of metals, such as Ca, Mg, Zn, Zr, Al, Ti and the like thereof, are preferred (see, for example, Japanese Patent Kokai Publication JP-A-60-69011 proposed by the present inventors). In particular, the fatty acids that melt at 40xc2x0 C. or higher are preferred.
If the number of carbon atoms is less than 12, the problem of stimuli to the skin tends to be raised. On the other hand, if the number of carbon atoms is more than 26, reactivity is lowered to render it difficult to achieve the meritorious effect of the present invention.
(Dextrin Fatty Acid Ester)
There is no limitation to the dextrin fatty acid ester employed in the present invention, such that it may be selected from esters constituted by dextrin and fatty acid or derivatives thereof. Examples of the dextrin fatty acid ester preferably include an ester having at least a partial structure in which a molecule of a C8 to C24 fatty acid is esterified to one of hydroxyl groups of a dextrin molecule, or the derivatives thereof, for example, an ester in which one or more C8 to C24 fatty acids is esterified to one or more hydroxyl groups of a dextrin molecule. The hydroxyl group of the ester thus obtained may or may not further be esterified by another fatty acid.
The esterification degree of the ester preferably is about 30 to 95% and more preferably is about 50 to 90%. If the esterification degree is less than 30%, oleophilicity is undesirably insufficient, whereas, if the esterification degree is higher than 95%, adhesion to the surface of the particulate powders is undesirably lowered, and therefore both cases are not preferable. Specifically, the esters may be enumerated by dextrin myristate, dextrin palmitate, dextrin stearate, dextrin coconut oil fatty acid ester, dextrin behenate, dextrin palmitate-2-ethylhexanoate and the like. Although the treating agent can be prepared by conventional methods, they may be readily acquired as commercial articles, such as xe2x80x9cRheopearl KLxe2x80x9d, xe2x80x9cRheopearl MKLxe2x80x9d, xe2x80x9cRheopearl TTxe2x80x9d, xe2x80x9cRheopearl KExe2x80x9d and xe2x80x9cRheopearl TLxe2x80x9d, manufactured by CHIBA FLOUR MILLING CO. LTD.
If the above-described various surface treating agents are used for constituting layer A (layer coated with the surface treating agent of the present invention), one or more of the compounds in the agents may be mixed for use as a surface treating agent to perform the targeted surface treating to constitute the coating layer (layer A).
(Organo Polysiloxane Modified at Sole Terminal End with Functional Group)
The organo polysiloxane modified at a sole terminal end with a functional group, such as the organo polysiloxane modified at a sole terminal end with a trialkoxy group, is preferably a compound having the following general formula (7):
(R33SiO)(R32SiO)n(SiR43)xe2x80x83xe2x80x83(7)
where plural R3s in the above general formula are all independent of each other and respectively denote C1 to C10 saturated or unsaturated hydrocarbon residual groups, whereas plural R4s in the above general formula are all independent of each other and respectively denote any one of a hydrogen atom, a hydroxyl group, a halogen atom (Cl, Br, I, etc.), silazane group, isopropenoxy group and 1 to 4 carbon atom lower alkoxy groups, n being an integer of 10 to 100.
If the value of n is less than 10, the reaction proceeds too quickly so that hydrolysis is accelerated, by the acidic point or basic point (isoelectric point) of the powder and/or trace quantities of moisture affixed to the powder surface, to cause cross-linking polymerization which causes the coating layer to become gelated or a semi-solid state and hence the targeted oily coating layer cannot be obtained. If the n value exceeds 100, reactivity is drastically lowered and the coating layer on the surface of the particulate powders becomes non-uniform. Therefore, dispersibility in the oleophilic liquid cannot be expected so that no contribution can be expected towards the hydrophobic property and oleophilicity.
As the surface treating agent for layer B, the products xe2x80x9cX-24-9826xe2x80x9d, xe2x80x9cX-24-9171xe2x80x9d and xe2x80x9cX-24-9174xe2x80x9d manufactured by SHIN-ETSU CHEMICAL CO. LTD. may be conveniently purchased and used.
(Alkylsilane Modified at the Sole Terminal End with a Functional Group)
Among the alkylsilanes modified at the sole terminal end with a functional group, there are a variety of silane derivatives, such as alkyl trialkoxysilane modified at the sole terminal end with a functional group. The compound represented by the following general formula (8) is preferably employed:
xe2x80x83R5SiR63xe2x80x83xe2x80x83(8)
where R5 preferably denotes an alkyl group having a 6 to 30 carbon atom straight chain or side chain, plural R6s are independent of one another and respectively denote any one of a hydrogen atom, a hydroxyl group, a halogen atom, such as Cl, Br, I, etc. and a 1 to 4 number of carbon atom lower alkoxy group.
If the number of carbon atoms of R5 is less than 6, no lubricious feeling can be obtained, whereas, if it exceeds 30, reactivity is drastically lowered such that the coating layer on the surface of the particulate powders tends to be non-uniform. The result is that dispersibility to the oleophilic liquid cannot be achieved so that no contribution is made to the hydrophobic nature and oleophilicity of the powders being treated. Moreover, the coating layer becomes a solid coating layer so that the meritorious effect of the present invention, that is the lubricious feeling, cannot be obtained.
The treating agent may conveniently be acquired as a marketed product, such as xe2x80x9cTSL 8185xe2x80x9d and xe2x80x9cTSL8186xe2x80x9d manufactured by TOSHIBA SILICONE CO. LTD., xe2x80x9cSIO6645.0xe2x80x9d manufactured by CHISSO CORPORATION, xe2x80x9cKBM-3103xe2x80x9d manufactured by SHIN-ETSU CHEMICAL CO. LTD. and xe2x80x9cA-137xe2x80x9d manufactured by NIPPON UNICAR CO. LTD.
(Branched Fatty Acid)
There is no limitation to the branched fatty acids employed in the present invention if the fatty acid used has a branched alkyl group. It is preferred to use 8 to 22 carbon atom branched fatty acids which are superior in dispersibility and which give an oily feeling when used on the powders. Examples of marketed products include isononanoic acid, 2-ethylhexoic acid, isotridecanoic acid, isomyristic acid, isopalmitic acid, isostearic acid and isobehenic acid. The branched fatty acids with the number of carbon atoms less than 8 or more than 22 are not desirable since the meritorious effect of the present invention is not achieved.
For the various surface treating agents described above, any one may be used, for the surface treating agents, or plural compounds for the surface treating agents may be used in combination.
The treating agent used for layer B is a compound which covers the outermost layer of the powdered material, so that it significantly affects the dispersibility or aesthetic feeling of the treated powders. This treating agent has a functional group only at the sole terminal end, such that an organopolysiloxane chain, straight alkyl chain or a branched alkyl chain, as a main chain molecule, becomes freely mobile.
The dispersibility into the oleophilic liquid and the lubricious feeling is due to a large extent to the length of this main chain. The organopolysiloxane modified at the sole terminal end with a functional group has a polymerization degree of the order of 10 to 100, whereas, with the alkylsilane modified at the sole terminal end with a functional group, the number of carbon atoms of the alkyl group is 6 to 30 and, with the branched fatty acid, the number of carbon atoms is of the order of 8 to 22, so that coating as applied gives surface-treated powders having a lubricious feeling and excellent (super)-dispersibility.
If the organo polysiloxane modified at the sole terminal end with a functional group, with the polymerization degree less than 10, is applied, the lubricious feeling and dispersibility is slightly lowered. Especially, in the case of dispersions into oleophilic liquids, the dispersibility and dispersion stability, which is the main characteristics of the present invention, cannot be achieved. It is hypothesized that the short length of the organo siloxane chain, directly affects and minimizes its affinity for oleophilic liquids.
If the range of the polymerization degree is too high, specifically exceeds 100, or the number of carbon groups of the alkyl group in the alkylsilane modified at the sole terminal end with a functional group or the branched fatty acid is excessive, (specifically the number of carbon atoms exceeds 30, and the number of carbon atoms exceeds 24, respectively), reactivity is drastically lowered, with the result that the degree of hydrophobic nature or oleophilicity is lowered to give a sticky, heavy feeling.
(On the Coating Amount for Powder)
Such an amount of the surface treating agent constituting a solid coating layer (layer A) on the surface of the particulate powder, which is just short of the amount to uniformly coat the particle surface is desirable. If the surface treating agent is of such a quantity as to uniformly cover the particle surface completely, the particle tends to become flocculated to neighbouring particles, which is not desirable. The amount of the surface treating agent just short of the amount which uniformly coats the particle surface, is such a coating amount which forms an emulsifying layer in a test on the coating uniformity, which is one of the evaluation items shown in the Examples in the specification of this application. This test is evaluated when layer A only, is applied to the powder.
In the present invention, layer A needs to be solid at room temperature because it is easier to coat the outermost surface of the particulate powder with the least amount of surface-treating agent to give an oleophilic uniform coating than with a liquid compound at room temperature. On the other hand, it is necessary for layer B to be liquid at room temperature because the outermost layer of the particulate powder must be liquid-like by coating the outermost layer of the particulate powder with a liquid molecule. It is also desirable that the particulate powders, while appearing to be powders, present a microscopic appearance that the particulate powders are dispersed in a liquid. The required coating quantity is selected to meet this condition.
It is hypothesized that even when these powder particles come close to each other, they do not become flocculated together because the particle surface is coated with these liquid molecules, to give excellent dispersibility. The surface of the particulate powder is already wet and hence is superior in affinity to the oleophilic liquid to present optimum dispersibility. In particular, it may be premeditated that, in an oleophilic liquid, layer B liquid molecules are stretched to their maximum length and dispersed throughout to obstruct contact between particles (steric hindrance) to achieve dispersion stability. The compounds for layers A and B are selected, depending on the system into which the powders to be coated are mixed into and on the type of the oleophilic liquid as the dispersion medium. For example, if it is desired to prepare a pressed powder without any addition of binders, layers A and B are coated with a dextrin fatty acid ester and with a branched fatty acid, respectively. If dispersibility in silicone oil is required, layers A and B are coated with an organo polysiloxane and with an organo polysiloxane modified at the sole terminal end with a functional group, respectively. If dispersibility in a volatile hydrocarbon is required, layers A and B are coated with a fatty acid and with an alkylsilane modified at the sole terminal end with a functional group. If dispersibility in an ester oil is required, layers A and B are coated with N-acylamino acid and with branched fatty acid, respectively.
In the present invention, the xe2x80x9coleophilic liquidxe2x80x9d is an oily material, which is used as a cosmetic, which is liquid or solid at room temperature and which is difficult to solubilize in water. Specific examples of the oleophilic liquid are oils and fats, such as safflower oil, soybean oil, evening primrose oil, grapeseed oil, rose hip oil, ququinut oil, almond oil, sesame oil, wheat bran oil, corn oil, cottonseed oil, avogado oil, olive oil, camellia oil, pasic oil, castor oil, peanut oil, cobnut (hazelnut) oil, macademia nut oil, medoform oil, cacao fat, sear fat, wood wax, coconut oil, palm oil, palm kernel oil, beef fat, horse meat fat, mink oil, milk fat, egg yolk oil and turtle oil, waxes, such as bees wax, whale wax, lanolin, carnauba wax, candelilla wax and hohoba oil, hydrocarbons, such as fluid paraffin, fluid isoparaffin, squalane, squalene, vaseline, paraffin sericine and microcrystalline wax, fatty acids, such as lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, linolic acid, undecylenic acid, hydroxy stearic acid and lanolin fatty acid, higher alcohols, such as myristyl alcohol, cetyl alcohol, cetostearyl alcohol, stearyl alcohol, aralkyl alcohol, behenyl alcohol, oleyl alcohol, hohoba alcohol, batyl alcohol, cholesterol, phytosterol, lanolin alcohol and isostearyl alcohol, esters, such as ethyl oleate, isopropyl myristate, cetyl octanoate, diisostearyl malate and glyceryl tricaprylate, silicones, such as methyl polysiloxane, methyl phenyl polysiloxane and decamethyl cyclotetrasiloxane, organic solvents, such as ethyl acetate, butyl acetate and toluene, anionic, cationic, nonionic and amphoteric surface active agents (surfactants) A preferred method for dispersing the coated powders of the present invention in an oleophilic liquid, that is a solid at room temperature may be to disperse the powders in the oleophilic liquid liquefied by heating to a temperature higher than its melting point (temperature). This method is commonly used for a capsule or a preparation form in which a larger amount of wax solid or the like at room temperature is mixed, such as in lipsticks.
The amount of the surface treating agent for forming the solid coating layer is preferably the same as that of the liquid surface treating agent on comparison based on weight or is less than that of the liquid surface treating agent (Axe2x89xa6B) Therefore, in coating the powder surface with the surface treating agent which gives a solid coating layer at room temperature, and in coating the powder surface with the surface treating agent which gives a liquid coating layer at room temperature, the mixing ratio of the respective coating layers for the powder is preferably set so that the amount in weight of the surface treating agent for the liquid coating layer (layer B) is equal to or greater than that of the surface treating agent for the solid coating layer (layer A).
If the amount in weight of the surface treating agent for the solid coating layer is larger than that of the surface treating agent for the liquid coating layer, the dispersibility of the resulting surface-treated powder in an oleophilic liquid may tend to be poor to some extent.
The amount of the surface treating agent for the solid coating layer is preferably a necessary minimum amount capable of uniformly coating the particulate powder, as described above. If this amount of the surface treating agent is larger than the necessary minimum amount, the particulate powder particles are simply flocculated, such that, if the particulate powder particles are coated with the surface treating agent for the coating layer that is a liquid at room temperature, it is not possible to achieve superior dispersibility in the oleophilic liquid of the produced surface-treated powder. Since the necessary minimum amount is varied with the powder type and with the treating method, it is necessary to check an appropriate coating amount by experimentation beforehand.
The coating amount of layer A that is a solid at room temperature differs with the type and the specific surface area of the powder treated according to the present invention. It is, however, preferably about 0.1 to 15 weight parts, more preferably about 0.1 to 10 weight parts and further more preferably about 0.5 to 6 weight parts in reference to 100 weights parts of the powder material prior to the surface treating (without the layers). If this amount of the surface treating agent is less than 0.1 weight part, it may not be possible to produce a uniform coating layer on the powder surface. On the other hand, if the coating amount exceeds 15 weight parts, the particulate powder particles may be simply flocculated, such that, even if the particulate powder particles might be coated with the surface treating agent for the coating layer liquid at room temperature, it may not be possible to achieve superior dispersibility in the oleophilic liquid of the produced surface-treated powder.
In a similar manner, the coating amount of the surface treating agent for layer B is preferably about 0.1 to 30 weight parts, more preferably about 0.5 to 20 weight parts and further more preferably about 0.5 to 15 weight parts, in reference to 100 weight parts of the powder material prior to the surface treating (without the layers). If the coating amount is lower than the above range, aesthetic feeling, adhesion to the skin and dispersibility are undesirably lowered. If the coating amount exceeds the above range, the amount of the free treating agent not reacted with the surface of the particulate powder particles is undesirably increased, however, the resulting surface-treated powder is not improved in dispersibility in the oleophilic liquid. Accordingly, such both cases are not preferable.
(Coating Method)
As a method for coating the powder with layer A, as a first layer, preferably a surface treating agent for forming a coating layer, preferably solid at room temperature, and further with layer B, as a second layer, preferably a surface treating agent for forming a coating layer, preferably liquid at room temperature, any suitable known methods in coating a surface treating agent may be used. The following are typical examples, of the coating method:
1. A dry method consisting of mixing e.g., a solid surface treating agent by a Henschel mixer, a super-mixer or the like, mixing a liquid surface treating agent to the resulting system and drying the resulting mixture;
2. A method consisting of dispersing the powder to be treated in water or in an organic solvent by a mechano-chemical type of mill, such as a ball mill, a sand grinder or the like, mixing and fixing e.g., a solid surface treating agent, further mixing e.g., a liquid surface treating agent into the system, removing the solvent and drying the resulting system (mixture); and
3. A method consisting in contacting the powder to be treated in a high-speed gas stream such as one obtained in a jet mill, with e.g., a solid surface treating agent for coating, and further contacting the resulting system with e.g., a liquid surface treating agent for coating, as described in Japanese Patent Kokoku Publication JP-B-6-59397 proposed by the present inventors, the whole content of which is incorporated in this specification by reference. In particular, a treating method by the jet method is preferably applied to the fine particulate powder having a primary particle size below a submicron diameter or equal to a submicron diameter.
It is sufficient if the xe2x80x9ctreating methodxe2x80x9d used herein in general may be a hydrophobic treating method applied to surface treating of the powdered material (substrate). Although the dispersibility in the oleophilic liquid is slightly inferior, it is possible to mix the surface treating agent (for layer A), preferably a solid at room temperature with the surface treating agent (for layer B), preferably a liquid at room temperature together and to make the resulting mixture to effect the coating simultaneously.
The powdered material (powder) to be surface-treated in accordance with the present invention may be coated with an oxide or a hydrous oxide of, for example, at least one of aluminium, calcium, magnesium, cerium, silicon, zirconium, titanium, zinc, iron, cobalt, manganese, nickel and tin, for improving compatibility with the surface treating agent and bonding tendency thereof thereto. In such case, the powder so coated corresponds to the powdered material to be coated or treated according to the present invention, that is the powdered material (substrate; base material) prior to coating with layer A in the present invention.
The amount of mixing of the so-produced coated powder to cosmetic is arbitrarily selected depending on the properties of the cosmetic. However, the mixing amount of the powder in the entire composition is preferably about 0.1 to 100 wt %, more preferably about 1 to 100 wt % and further more preferably about 1 to 99 wt %. It is possible for the oleophilic liquid to be contained in the total composition. For example, a trace amount of the fine particles of the zinc oxide, as an astringent, may be occasionally contained in an amount e.g., of 0.1 wt % or so in a cosmetic. On the other hand, loose powders and pressed powders or the like, usually mixed with an oily agent(s) in an amount of a few wt % in the entire formula, may be possibly formulated without mixing the corresponding oily agent(s) in the present invention.
Also, one or more of the coated powders obtained in accordance with the present invention may be mixed as appropriate to these coated powders.
In addition, it is more preferred to mix the coated powder of the present invention in e.g., cosmetic, without employing the powder used in other conventionally used powders, in order to demonstrate the meritorious effect of the present invention more prominently. However, routinely used powders may also be used as a mixture in a range not detracting from the meritorious effect of the present invention.
The cosmetic containing a powder having two coating layers, according to the present invention, may be enumerated by finishing cosmetic, such as in a powder foundation, liquid foundation, oily foundation, stick foundation, pressed powders, face powders, lipstick, lip gloss, cheek rouge, eye shadow, eye brow, eye liner, mascara, aqueous nail enamel, oily nail enamel, emulsion type nail enamel, enamel top coat, enamel base coat and the like, cosmetic for skin, such as emollient cream, cold cream, whitening cream, emulsion, aqueous cosmetic, cosmetic liquid, carmine emulsion (lotion), liquid face washing agent, face washing foam, face washing cream, face-washing powder, makeup cleansing, body gloss and the like, cosmetic for hair, such as hair gloss, hair cream, hair shampoo, hair rinse, hair color, hair brushing agents and the like, and others, for example, sunscreen cream, san-tan cream, emulsion, soap, bath agent, perfume and the like.
For the cosmetic to which the powders coated with two layers (layers A and B) of the surface treating agents are mixed in accordance with the present invention, pigment dispersing agents, oily agents, surfactants, UV absorbers, anti-septics, anti-oxidants, film forming agents, humidifying (moisture-retaining) agents, thickening agents, dyestuffs, pigments, perfumes and the like may be used if so desired.
This application is claiming the priority based on the Japanese patent applications serial Nos. 194570/1999 and 073261/2000, filed on Jul. 8, 1999and filed on Mar. 16, 2000, respectively and the contents of these 2 Japanese applications are incorporated in the specification of this application by reference, if necessary.